>> he strikes me as the most like us. we'll full of contradictions. >> reporter: he writes that this messenger of god married a 6-year-old old and consummated the marriage when she was 9. some scholars disagree with that characterization. he has publicly suggested that the holy koran might have been written by jews. assigned the task of following the prophet around. can you talk about it. >> it's one of few imagined characters in the book. >> reporter: did you mean to intimate that jews could have had a hand in writing the koran? >> i have wondered about that. >> reporter: but it is provocative. >> yeah, i have been careful not to say it in my book. >> reporter: you as a nonbeliever, are you worried that people who are devout believers will be anger with you? >> i wrote the book after a lot of thought. i wrote the book with deep respect for my muslim friends. >> reporter: are you concerned that somebody could issue a -- could call for you to be assassination? >> my kids are concerned. if that happens, i'll deal with it. i